node.js – Puppeteer – 协议错误(Page.navigate)：目标已关闭

正如您在下面的示例代码中看到的那样,我正在使用Puppeteer与Node中的一组工作人员按给定的URL运行多个网站截图请求：

const cluster = require('cluster');
const express = require('express');
const bodyParser = require('body-parser');
const puppeteer = require('puppeteer');

async function getScreenshot(domain) {
    let screenshot;
    const browser = await puppeteer.launch({ args: ['--no-sandbox', '--disable-setuid-sandbox', '--disable-dev-shm-usage'] });
    const page = await browser.newPage();

    try {
        await page.goto('http://' + domain + '/', { timeout: 60000, waitUntil: 'networkidle2' });
    } catch (error) {
        try {
            await page.goto('http://' + domain + '/', { timeout: 120000, waitUntil: 'networkidle2' });
            screenshot = await page.screenshot({ type: 'png', encoding: 'base64' });
        } catch (error) {
            console.error('Connecting to: ' + domain + ' failed due to: ' + error);
        }

    await page.close();
    await browser.close();

    return screenshot;
}

if (cluster.isMaster) {
    const numOfWorkers = require('os').cpus().length;
    for (let worker = 0; worker < numOfWorkers; worker++) {
        cluster.fork();
    }

    cluster.on('exit', function (worker, code, signal) {
        console.debug('Worker ' + worker.process.pid + ' died with code: ' + code + ', and signal: ' + signal);
        Cluster.fork();
    });

    cluster.on('message', function (handler, msg) {
        console.debug('Worker: ' + handler.process.pid + ' has finished working on ' + msg.domain + '. Exiting...');
        if (Cluster.workers[handler.id]) {
            Cluster.workers[handler.id].kill('SIGTERM');
        }
    });
} else {
    const app = express();
    app.use(bodyParser.json());
    app.listen(80, function() {
        console.debug('Worker ' + process.pid + ' is listening to incoming messages');
    });

    app.post('/screenshot', (req, res) => {
        const domain = req.body.domain;

        getScreenshot(domain)
            .then((screenshot) =>
                try {
                    process.send({ domain: domain });
                } catch (error) {
                    console.error('Error while exiting worker ' + process.pid + ' due to: ' + error);
                }

                res.status(200).json({ screenshot: screenshot });
            })
            .catch((error) => {
                try {
                    process.send({ domain: domain });
                } catch (error) {
                    console.error('Error while exiting worker ' + process.pid + ' due to: ' + error);
                }

                res.status(500).json({ error: error });
            });
    });
}

一些解释：

>每次请求到达时,工人都会处理它并在最后自杀
>每个工作人员使用单个页面创建一个新的浏览器实例,如果一个页面加载超过60秒,它将重试重新加载它(在同一页面中,因为可能已经加载了一些资源),超时为120秒
>完成后,页面和浏览器都将关闭

我的问题是,一些合法的域名出现了我无法解释的错误：

Error: Protocol error (Page.navigate): Target closed.

Error: Protocol error (Runtime.callFunctionOn): Session closed. Most likely the page has been closed.

我读了一些git问题(我现在找不到),当页面重定向并在开始时添加’www’时会发生这种情况,但我希望它是假的……
有什么我想念的吗？

我不能告诉你为什么会发生这种错误,但我也会遇到这几百个请求. puppeteer存储库上也有一个 issue about this.

您可能想要查看处理这些错误情况的库puppeteer-cluster,然后让您重试URL.它可以管理一组浏览器实例,甚至可以简化您的代码. (免责声明：我是作者)